The present invention relates to an easy-to-open bag made of a synthetic resin.
Conventionally there have been proposed various kinds of easy-to-open bags which can be readily opened by breaking the bag with a tear string.
U.S. Pat. No. 3,057,539 discloses a pouch having a string buried between the polyethylene coating and the substrate to which the extruded polymer is applied. The polyethylene lamina usually faces the interior of the pouch.
Due to such construction, when the string is pulled to open the pouch, the polyethylene coating remains intact and has to subsequently be pulled apart by hand in order to get to the contents of the pouch.
For resolving the above defects, U.S. Pat. No. 3,494,538 discloses an easy-to-open bag or container, wherein the bag comprises a lamina of polyethylene and a fibrous tear string securely embedded in the surface of the lamina which faces the interior of the bag and the tear string is impregnated with dewaxed shellac.
Due to such construction, the string adheres to the polyethylene securely.
However, since the string adheres to the polyethylene by compression of pressure rolls with the exception of heat-sealed perimeters, the adhering strength is still less than optimal. Therefore, the tear string cannot tear the bag sharply. Furthermore, dewaxed shellac contaminates the content of the bag.
Still furtheremore, in the U.S. Pat. No. 3,494,538, since the notches or slits are formed by cutting the outermost edge of the heat-sealed perimeters to form a pulling tab, the perimeter is destroyed considerably so that the bag cannot be used for any other usages after opening.
Accordingly, it is an object of the present invention to provide an easy-to-open bag which can obviate the above defects of the conventional bags.